The present invention is directed to mobile storage systems and, more particularly, to a brake or anti-drift arrangement for a mobile storage unit.
Mobile storage systems have long been utilized to store documents, books and other items in a high density manner that also allows for easy access to the items contained on any portion of the mobile storage system. These systems typically include a number of storage units movably mounted on rails that are secured to the floor of a room or other enclosure. By operation of a motive system associated with each of the storage units, individual units may be moved along the rails to expose a desired unit in order to retrieve the items contained therein.
The motive system for these types of storage units can be either a mechanical system or an electrical powered system. With a mechanical motive system, each storage unit is moved by manually activating the mechanical mechanism, such as a hand crank. The crank or other manual activation means is disposed directly on an endmost one of the storage units, and is mechanically connected, such as by a drive shaft, to wheels on the storage unit to move those wheels and the storage unit along the rails.
With regard to a powered electrical motive systems used for the storage units, the system is activated by utilizing a switch that is operably connected to an electrically-powered motor connected to a drive shaft that rotates wheels of the storage unit. The activation of the motor then causes the wheels of the storage unit to rotate in the selected direction to move the storage unit in the desired direction. When operation of the motor is stopped, a brake associated with the motor prevents further rotation of the drive shaft, so that movement of the storage unit automatically stops when power to the motor is cut off, and the brake of the motor functions to prevent the storage unit from drifting out of position once movement of the storage unit is stopped.
In a mobile storage system that utilizes a mechanical drive system, the motive power is manually supplied by a user. As such, systems of this type do not have a motor so that the braking function provided by the motor is not available when it is desired to stop movement of the storage unit. Because of this, the momentum of the storage unit can cause the storage unit not to stop immediately when the user stops the application of input power by operation of the input device, such as the hand crank. In addition, in systems such as this, it is possible for the storage of units to drift or roll away from a desired position when the motive power applied to the storage and is relieved. Such movement of the storage unit can be caused by uneven or unlevel floor or rail conditions, or by deflection of the floor and/or rails.
A number of braking or anti-drift systems have been developed to stop rotation of the wheels of a storage unit when the input force is removed, or to prevent unwanted movement of storage units when the storage units are stationary. Systems have been developed that stop rotation of the wheel directly through engagement of a braking member with the wheel itself or indirectly by engagement of a braking member with the axle of the wheel. While generally satisfactory in stopping further movement of the storage unit after the input force has been removed or preventing movement of stationary storage units, the amount of braking force is generally fixed. This can be problematic as the load on a storage unit may not be well matched to the fixed braking force that is applied by the braking system. If the braking force is too great, it may difficult for the input force to overcome the inertia of a heavily loaded storage unit as well as the braking force of the braking system to move the storage unit. If the braking force is too weak, it may not be sufficient to quickly stop translation of the heavily loaded storage unit when the input force is removed. Too much braking force can also be a problem for lightly loaded storage units. While initial translation of the storage unit may not be difficult, when the input force is removed, if the braking force is too great, the storage unit could effectively be jolted by the application of the braking force, causing objects stored on the storage unit to jostle or fall.
As a result, it is desirable to develop a braking or anti-drift device for manually operated storage units used in a mobile storage system that, while capable of providing the desired braking feature to the individual units within the storage system in order to prevent movement of stationary storage units or to brake storage units during movement, does not require electrical power and also has a relatively simple construction for easy incorporation with the storage units. Moreover, it is desirable to have a braking device that does not require activation by a user to be effective. There is also a desire have a braking device in which the amount of braking force that is applied can be adjusted as needed to tailor the braking device to the load of the mobile storage unit and to other conditions.
In accordance with the present invention, an anti-drift or braking device for a mobile storage unit includes a dual-ended and flexible band that forces a brake pad into contact with a brake member that rotates with the drive shaft or axle of a wheel of the mobile storage unit. Each end of the band is connected to a tensioning mechanism that applies a tensioning force to the ends of the band to tension the flexible band. The tensioning mechanism may include a tensioning actuator that allows for varying the tensioning force applied to the ends of the band to adjust the tension that the flexible band applies to the brake pad. The flexible band applies tension against the brake member regardless of the rotational direction of the brake member.
Therefore, in accordance with one aspect of the invention, a mobile storage system includes one or more mobile storage units and a drive arrangement interconnected with the one or more storage units for causing movement of the one or more storage units. The drive arrangement includes a rotatable drive shaft that rotates in response to application of an input force. The system also includes a brake arrangement that acts on the drive shaft when the input force on the drive shaft is relieved, in order to prevent stationary storage units from drifting and/or to assist in stopping the storage units. The brake arrangement includes a brake member mounted to and rotatable with the drive shaft. A flexible band is engaged with the brake member and defines a pair of ends that are engaged with a tensioning mechanism. The tensioning mechanism applies a tensioning force to the ends of the brake band to tension the brake band against the brake member.
The invention also contemplates a method of preventing or braking movement of a mobile storage system having one or more mobile storage units and a drive arrangement interconnected with the one or more storage units for causing movement of the one or more storage units is provided. The method includes imparting a rotational movement to a brake member in response to rotation of a drive shaft of the drive arrangement and then applying a braking force to the brake member by applying tension to a pair of ends defined by a flexible brake band that is engaged about the brake member. The braking force is operable to stop rotation of the drive shaft when an input force to the drive shaft is relieved, and to prevent drifting movement of stationary storage units.
In accordance with yet another aspect of the invention, a mobile storage support system includes a mobile support arrangement that supports one or more storage units, and the mobile support arrangement includes a rotatable drive shaft that rotates in response to the application of an input force. The support system further includes a brake arrangement that acts on the drive shaft when the input force on the drive shaft is relieved. The brake arrangement has a brake member that rotates in response to rotation of the drive shaft. A flexible brake band is engaged with the brake member and defines a pair of ends. A tensioning mechanism is engaged with the ends of the brake band and applies a tensioning force to the ends of the brake band to tension the brake band against the brake member.
The present invention offers a number of advantages over prior braking or anti-drift systems for mobile storage units. For example, the present invention provides uniform application of braking force on the brake member, as well as adjustability of the tension applied on the brake member. In this regard, the invention allows the tension be adjusted to accommodate the load on a storage unit. The invention also allows the tension to be adjusted as the elasticity of the flexible band varies over time or as a brake pad wears.
The present invention is relatively compact, less complex, and easy to install when compared to prior braking systems. In this regard, the invention can be used with a low profile carriage of a mobile storage unit. Furthermore, the invention can be used with carriageless mobile storage units. As will be appreciated in the description that follows, a relative small diameter brake member and a taut flexible band together with a brake pad can be used to brake a mobile storage unit.
It is therefore an object of the invention to provide a brake arrangement or anti-drift arrangement for use with a mobile storage unit that provides a uniform application of a braking force and also allows for adjustment of the braking force applied by the brake arrangement.
It is another object of the invention to provide a brake or anti-drift arrangement that requires an input force to overcome the braking force applied by the brake arrangement but does not require a user to disengage the brake arrangement. It is yet a further object of the invention to provide a brake arrangement that automatically applies a braking force when an input force is relieved rather than requiring a user to engage the brake arrangement.
It is another object of the invention to provide a brake arrangement that may be used with carriageless mobile storage units.
It is another object of the invention to provide a brake arrangement that may be used with mobile storage units that are moved by a mechanical motive system, but which also can be utilized with an electrical motive system.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.